PubMed HealthSearch

Biomedical subjects

M P Murray

Publications and source records attributed to M P Murray.

18 recordsLinked to original sources

Census adjustment and the distribution of federal spending.

In 1989, programs that use population counts to determine the distribution of their funds transferred $236 per capita to state and local governments. If the 1990 census were adjusted to reflect undercounting, about 40% of state and local governments would receive increased grants averaging $56 per miscounted person; other jurisdictions would lose an almost equal amount of grant money. The surprisingly small reallocations arise because 1) total funds allocated by population are essentially fixed; 2) allocations depend on other factors in addition to population; and 3) programs vary as to whether they allocate funds in direct or inverse proportion to population.

Community Health Services

Mutagenic activity of epoxy embedding reagents employed in electron microscopy.

Components of epoxy-based embedding media used in electron microscopy were examined for their mutagenicity in the Ames Salmonella system. The compounds, singly and in combination, were shown to be active with strain TA100 (base substitution indicator) but not with TA98 (frameshift indicator). When tested separately the epoxy resins Araldite, Epon, and vinyl cyclohexen dioxide (VCD) and the plasticizer diglycidyl ether of propylene glycol (DER-736) were found to be significantly mutagenic. These active compounds, in combination with liver mixed oxidase preparation (S9), showed increased mutagenicity over similar preparations in the absence of microsomal activation.

Epoxy Resins

A comparison of the funtional performance of patients with Charnley and Müller total hip replacement. A two-year follow-up of eighty-nine cases.

Measurements of functional performance in 35 cases with Charnley total hip replacement were compared with those of 54 cases with Müller replacement before surgery and at 6- and 24-month follow-up intervals. The measurements included strength of the hip abductor and adductor muscles, hip motion, the amount of weight borne on the involved limb during standing posture, multiple components of free-speed and fast walking, and force applied to canes and crutches. Both replacement groups improved significantly in most components of function. In fact, both groups reached or nearly reached the lower limits of normal variability in weight-bearing ability, cadence, and some components which relate to smoothness of walking performance. The groups with Müller and Charnley replacement differed most in some components of range of hip motion, hip muscle strength, and lateral lurching during walking.

Adult

Locomotion assistance through cane impulse.

The extent of locomotion assistance gained through cane usage by those with hip disorders is assayed. Employing as a standard the propulsive impulse delivered by each lower limb of a healthy young male, the cane is shown to supply about one-fifth the equivalent impulse, aside from other possible benefits. Full test values are given for nine handicapped subjects.

Adult

Function of the triceps surae during gait. Compensatory mechanisms for unilateral loss.

We studied the gait of a woman who was normal except for surgical excision of the gastrocnemius and soleus muscles. She was able to compensate for nearly all of her abnormalites of gait by excessive lateral pelvic tilt and prolonged quadriceps activity. Her mild disability, as regards gait, consisted of inability to increase walking speeds beyond the normal pacing. However, despite uneven step lengths, she had uniform forward progression. She had excessive dorsiflexion of the ankle and diminished plantar flexion on the involved side even though the retained plantar flexors could provide 38 per cent of her normal plantar flexor strength.

Adult

Walking patterns of men with parkinsonism.

Interrupted-light photography was used to record the simultaneous displacement patterns of multiple body segments of 44 patients with parkinsonism during free-speed and fast walking to quantitatively characterize their gait peculiarities. The patients were categorized into three disability groups according to their independence in activities of daily living. Their measurements of walking performance were compared to those of normal men. The gait components of the patients, which related systematically to the degree of disability, were: step lengths, vertical excursions of the head, extension of the hip and knee of the backward-directed limb at the onset of contralateral weight bearing, toe-floor distance at the onset of weight bearing, and rotation of the thorax.

Activities of Daily Living

Maximum isometric knee flexor and extensor muscle contractions: normal patterns of torque versus time.

Isometric torque of the knee flexor and extensor muscles were recorded for 5 seconds at three knee joint positions. The subjects included healthy men in age groups from 20 to 35 and 45 to 65 years of age. The amplitudes and duration of peak torque and the time to peak torque were measured for each contraction. Peak torque was usually maintaned less than 0.1 second and never longer than 0.9 second. At each of the three angles, the mean extensor muscle torque was higher than the mean flexor muscle torque in both age groups, and the mean torque for both muscle group was higher among the younger than among the older man. The highest average torque was recorded at the knee angle of 60 degrees for the extensor muscles and 45 degrees for the flexor muscles, but this was not always a stereotyped response either for a given individual or among individuals.

Adult

Roentgenographic measurements after Müller total hip replacement. Correlations among roentgenographic measurements and hip strength and mobility.

In fifty-two patients with Müller total hip replacement, roentgenographic measurements of prosthetic component positioning were correlated with hip-muscle strength and mobility measurements. Compared with the normal side, the average position of the center of the prosthetic head was more medial and superior in the pelvis, and the greater trochanter was more distal and lateral. Increasing neck length (distance from the center of the prosthetic head to the lesser trochanter) and a more distal position of the greater trochanter were among the measurements that related favorably to measurements of patient function. More superior placement of the center of the prosthetic head in the pelvis was associated with a more superior position of the lesser trochanter, which related adversely to function.

Aged

A comparison of plantar flexion torque with and without the triceps surae.

Torque generated about the ankle joints during maximum isometric contraction of the plantar flexor muscles was measured on a subject 4 months after unilateral excision of the entire triceps surae. Resulting torque output on the operated limb was 327 kg-cm, or 38 per cent of the 871 kg-cm total for the sound limb.

Biomechanical Phenomena

A method of measuring the duration of foot-floor contact during walking.

A new method for monitoring the durations of foot-floor contact during walking is described. The method uses a screen walkway and conducting paper on the soles of the shoes as parts of an electrical circuit. The materials used are identified and circuit diagrams are provided. Several clinical applications and advantages and disadvantages of the method are discussed.

Biomechanical Phenomena

Kinesiology after McKee-Farrar total hip replacement. A two-year follow-up of one hundred cases.

Measurements of functional performance were made before and at six and twenty-four months after 100 McKee-Farrar total hip replacements in eighty-three patients. The measurements included: range of motion of the hip, hip-muscle torque, weight-bearing activity during standing, forces applied to canes or crutches, and multiple components of walking performance. In the absence of serious complications, most patients had improvement in most components of function, with greater gains occurring during the first six months and lesser but continued gains between the sixth and twenty-fourth postoperative months. Patients with serious operative complications, postoperative infections, or component loosening showed declines in almost every component of function tested.

Biomechanical Phenomena

Normal postural stability and steadiness: quantitative assessment.

A force platform was utilized to provide a new and sensitive means to measure postural steadiness and stability. Normal standards are presented for the center of pressure of the vertical supportive force during standing and sustained weight-shifting of normal men in three age groups. Two distinguishing characteristics were seen for normal upright posture: (1) a large area of stability over which weight can be safely shifted and maintained, and (2) steadiness such that the center of pressure fluctuates incessantly, traversing large total excursions, while remaining remarkably close to the mean point. The youngest age group showed the greatest steadiness and stability and the oldest group showed the least.

Adult

Walking patterns of men with unilateral surgical hip fusion.

The gait of men with unilateral hip fusion is somewhat slow, asymmetrical, and arrhythmic as compared with that of normal men. Compensation for absent hip motion is accomplished by increased transverse and sagittal rotation of the pelvis, increased motion in the sound hip, and increased flexion of the knee throughout the stance phase on the fused side. Relationships between the fusion position, certain physical traits, and walking performance suggest that the best gait can be expected in young patients who have free motion of the lumbar spine, the sound hip, and the knee on the side of fusion, and who have equal limb lengths and a hip fused in a position that does not include excessive adduction.

Adolescent

Kinesiologic measurements of functional performance before and after geometric total knee replacemtn: one-year follow-up of twenty cases.

Kinesiologic measurements were made in patients with severe arthritis before and after geometric total knee replacements to evaluate the nature, rate and extent of change in their functional ability. Preoperatively, patients with rheumatoid arthritis functioned at lower levels than patients with osteoarthritis. Most patients with rheumatoid arthritis improved steadily after surgery, while progress of those with osteoarthritis was often irregular. The group with rheumatoid arthritis improved more than those with osteoarthritis, but they did not generally reach the functional level attained by the patients with osteoarthritis, and neither group reached the lower limits of normal variability 1 year postoperatively. On the average, both groups gained knee extensions, lost knee flexion, and gained isometric knee flexor muscle strength postoperatively. Every patient with osteoarthritis lost extensor muscle strength 1 year after surgery, while most with rheumatoid arthritis gained. During quiet standing, most patients had straighter knees postoperatively and bore a greater percent of body weight on the operated limb. Patients with rheumatoid arthritis improved more than patients with osteoarthritis in the type and amount of force applied to canes and crutches. Most patients walked faster postoperatively, took longer and more rapid steps, improved the pattern of knee motion used, and had smoother forward, lateral and vertical head motion.

Aged

Comparison of functional performance after McKee-Farrar, Charnley, and Muller total hip replacement. A six-month follow-up of one hundred sixty-five cases.

Measurements of functional performance were compared before and at 6 months after 58 McKee-Farrar, 50 Charnley, and 57 Muller total hip replacements in 143 patients. The measurment included: range of motion of the hip, hip abductor and adductor-muscle torque, weight-bearing activity during standing, forces applied to canes or crutches, and multiple components of walking performance. Each group of patients improved significantly after surgery in all of the components measured. Early postoperative differences among the 3 groups were found with respect to pain ratings, impressions of hip status, hip motions, muscle torque, the number of patients using assistive devices, and certain components of walking performance. There is nothing to suggest that the performance of any 1 group is distinctly better or worse than that of any other group 6 months after surgery. On the basis of average values, each group improved in every component of function and it is gratifying that, except for a few patients who developed postoperative infection, each patient could be considered to have successful reconstruction.

Adult